The invention relates to a plate brake tester for testing the brakes of a motor vehicle, comprising two pair of tread plates one beside the other, each of said tread plates having a measuring device for measuring the force exerted on the tread plate, a processing unit for processing measuring signals provided by the measuring devices and a display for displaying the measuring results, further comprising a weighing device for determining the weight of the front axle and the rear axle of the vehicle, respectively, said processing unit being adapted to compute the braking retardation from the measured brake forces and the total weight of the vehicle.
Such an apparatus is very suitable for testing the brakes of a motor vehicle, because the brakes are tested under circumstances as will also occur during braking on the road. An important criterion for evaluating the operation of the brakes of a vehicle is the ratio of the braking forces exerted by the front wheels and the braking forces exerted by the rear wheels, which ratio can be indicated as brake force ratio front axle/rear axle. In many countries the government requires that this brake force ratio is in any case such that during braking on the road the front wheels will always be the first to skid. For these reasons car manufacturers choose a brake force ratio with such a safety margin that rear wheel skid cannot occur. However this results in a lower maximum obtainable braking retardation because the brake force which can be transfered by the rear wheels on the road is lower than the dynamic weight on the rear wheels. Up to the present there is no brake tester available by means of which a test of the brakes of a motor vehicle can be done in simple and for the garage industry economic manner in order to check whether the brake force ratio meets certain requirements like for example the requirements of the government.